The MR system is an imaging device, and is intended to provide the physician with physiological and clinical information, obtained non-invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, oblique, and curved cross-sectional images that display the internal structure of the head, body, or extremities. The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density, spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and flow. When interpreted by a trained physician, these images provide information that can be useful in diagnosis determination.

Device Description

The STRATIS Magnetic Resonance Diagnostic Device is being enhanced by the STRATIS II System-level upgrade to increase the clinical utility of the STRATIS in the stationary configuration. The STRATIS II is provided in a stand-alone configuration, and as an upgrade path to existing STRATIS installations. STRATIS II System-level upgrade enhancements include a new Back End user interface featuring a workstation-based User Console, implementing a graphical user interface operating system and task card-style operations (OpenWindows™). A new Front End provides real-time system control, data acquisition and reconstruction, implements all image acquisition sequences available on current STRATIS, and provides two additional types of image acquisition sequences: TRSG (time-reversed steady-state acquisition with rewinded gradient echo) and RSSG (rf spoiled steady-state acquisition with rewinded gradient echo). Other enhancements include an elliptical T/R QD Body Coil, a patient physiological gating package, and phased-array RF coils.

AI/ML Overview

This document describes the Hitachi STRATIS II Magnetic Resonance Diagnostic Device, but it does not contain any information regarding acceptance criteria, performance studies, or ground truth establishment.

The provided text is a 510(k) premarket notification for an MRI system, indicating that the device is being enhanced to increase clinical utility. It details the device's function, scientific concepts of MRI, physical and performance characteristics, and intended use. The key aspect of the submission is that the device's technological characteristics are "Identical to the Predicate Device" (Hitachi STRATIS with Version 6-05 Operating System Software).

Therefore, I cannot provide the requested information. The document focuses on demonstrating substantial equivalence to a predicate device, which typically relies on showing that the new device has the same technological characteristics and intended use as a device already cleared by the FDA, rather than presenting new performance studies against specific acceptance criteria.

To answer your request for acceptance criteria and study details, this information would need to be present in a different type of regulatory submission or an accompanying technical report.

Summary

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FEB 26 1998

SUBMITTER INFORMATION: 1.0

K974498

Hitachi Medical Systems America 1.1 Submitter: 1963 Case Parkway Twinsburg, OH 44087 PH: 216 425-1313 FX: 216 425-1410
James Jochen Rogers 1.2 Contact:
November 26, 1997 1.3 Date:

DEVICE NAME: 2.0

Radiology 2.1 Classification Panel:
892.1000 Magnetic Resonance Diagnostic Device 2.2 Classification Number:
System, Nuclear Magnetic Resonance Imaging 2.3 Product Nomenclature:
Product Code(s): 90LNH 2.4 90MOS (Magnetic Resonance Specialty Coil)
STRATIS II 2.5 Trade/Proprietary Name:
PREDICATE DEVICE(s): 2.6

Hitachi STRATIS Hitachi STRATIS with Version 6-05 Operating System Software

DEVICE DESCRIPTION: 3.0

FUNCTION 3.1

STRATIS II System-level upgrade enhancements include a new Back End user interface featuring a workstation-based User Console, implementing a graphical user interface operating system and task card-style operations (OpenWindows™). A new Front End provides real-time system control, data acquisition and reconstruction, implements all image acquisition sequences available on current STRATIS, and provides two additional types of image acquisition sequences: TRSG (time-reversed steady-state acquisition with rewinded gradient echo) and RSSG (rf spoiled steady-state acquisition with rewinded gradient echo). Other enhancements include an elliptical T/R QD Body Coil, a patient physiological gating package, and phased-array RF coils.

SCIENTIFIC CONCEPTS 3.2

Magnetic Resonance (MR) is based on the fact that certain atomic nuclei have electromagnetic properties which cause them to act as small spinning bar magnets. The most ubiguitous of these nuclei is hydrogen, which makes it the primary nucleus used in current imaging experiments in magnetic resonance. When placed in a magnetic field, there is a slight net orientation or alignment of these atomic nuclei with the magnetic field. The introduction of a short burst of radiofrequency (RF) excitation of wavelength specific to the magnetic field strength and to the atomic nuclei under consideration can cause a reorientation of the proton's magnetization vector. When the RF excitation is

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removed, the proton relaxes and returns to its original orientation. The rate of relaxation is exponential, and varies with the character of the proton and its adjacent molecular environment. This reorientation process is characterized by two exponential relaxation times called T1 and T2 which can be measured.

These relaxation events are accompanied by an RF emission or echo which can be measured and used to develop a representation of these emissions on a three dimensional matrix. Spatial localization is encoded into the echo by varying the RF excitation and by appropriately applying magnetic field gradients in x, y, and z directions, and changing the direction and strength of these gradients. Images depicting the spatial distribution of NMR characteristics of the nuclei under consideration can be constructed by using image processing techniques similar to those used in CT.

For magnetic fields up to 1.5T, the RF frequencies commonly used range up to 65MHz. The RF fields have pulse powers from several watts to greater than 10 kilowatts, and repeat at rates from once every few seconds to greater than fifty per second. The timevarying magnetic gradient fields have a typical duration of sub-millisecond to several milliseconds.

3.3 PHYSICAL AND PERFORMANCE CHARACTERISTICS

MR is currently of great interest because it is capable of producing high quality anatomical images without the associated risks of ionizing radiation. In addition, the biological properties that contribute to MR image contrast are different from those responsible for x-ray image contrast. In x-ray imaging, differences in x-ray attenuation, largely based on differences in electro density are responsible for the contrast observed in x-ray images. In MR imaging, differences in proton density, blood flow, and relaxation times T1 and T2 all may contribute to image contrast. In addition, by varying the duration and spacing of the RF pulses, images may be produced in which the contrast is primarily dependent on T1 relaxation, T2 relaxation, proton density, or a combination of all three.

4.0 DEVICE INTENDED USE:

The MR system is an imaging device, and is intended to provide the physician with physiological and clinical information, obtained non-invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, oblique, and curved cross-sectional images that display the internal structure of the head, body, or extremities. The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density, spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and flow. When interpreted by a trained physician. these images provide information that can be useful in diagnosis determination.

●	Anatomical Region:	Head, Body, Spine, Extremities
●	Nucleus excited:	Proton
●	Diagnostic uses:	2D T1-/T2-weighted imagingT1, T2, proton density measurementsMR Angiographyimage processing
●	Imaging capabilities:	2D, 3D Spin Echo (SE)2D, 3D Fast Spin Echo (FSE)2D Inversion Recovery (IR)2D, 3D Fast Inversion Recovery (FIR)2D, 3D Gradient Echo (GE)2D, 3D Steady state acquisition with rewinded GE (SARGE)

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2D, 3D RF-spoiled SARGE (RSSG) 2D, 3D Time-reversed SARGE (TRSG) MR Angiography 2D, 3D TOF 2D, 3D TOF RSSG ECG, Peripheral Gating Fat Suppression

DEVICE TECHNOLOGICAL CHARACTERISTICS: 5.0

Identical to the Predicate Device.

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Image /page/3/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo is circular and contains the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of an eagle.

FEB 26

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

James Jochen Rogers Manager, Regulatory Affairs Hitachi Medical Systems America 1959 Summit Commerce Park Twinsburg, OH 44087-2371

Re: K974498

STRATIS II (Magnetic Resonance Diagnostic Device) Dated: November 26, 1997 Received: November 28, 1997 Regulatory class: II 21 CFR 892.1000/Procode: 90 LNH

Dear Mr. Rogers:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the ensetment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Commetic Act (Act.). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your derice can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (OS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Resister. This response to your premarket notification submission does not affect any obligation you might have under sections 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predication for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 80) and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4613. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address "http://www.fda.gov/cdch/dsmaldsmam.html"

Sincerely yours,

Lillian Yin, Ph.D.

Lillian Yin, Ph.D Director, Division of Reprod Abdominal, Ear, Nose and Thro and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):

Device Name: STRATIS II

Indications for Use:

Anatomical Region: Head, Body, Spine, Extremities
Nucleus excited:
Diagnostic uses:

Proton 2D T1- / T2-weighted imaging T1. T2. proton density measurements MR Angiography image processing

Imaging capabilities:
2D, 3D Spin Echo (SE) 2D, 3D Fast Spin Echo (FSE) 2D Inversion Recovery (IR) 2D, 3D Fast Inversion Recovery (FIR) 2D.3D Gradient Echo (GE) 2D, 3D Steady state acquisition with rewinded GE (SARGE) 2D. 3D RF-spoiled SARGE (RSSG) 2D, 3D Time-reversed SARGE (TRSG) MR Angiography 2D, 3D TOF 2D, 3D TOF RSSG ECG, Peripheral Gating Fat Suppression

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

(Division Sign-Off)
Division of Reproductive, Abdominal, ENT,
and Radiological Devices
510(k) Number K974498

)
Prescription Use X
(Per 21 CFR 801-109
OR
Over-the-Counter Use __

(Optional Format 1-2-96)

Regulation Number and Section

N/A